During orthopedic procedures, a fracture table functions to stabilize the patient and to deliver traction to one or both of the lower limbs of the patient by putting the legs in tension. In many orthopedic procedures it is necessary to abduct or adduct one or both of the legs (i.e. pivot it around its corresponding hip), while the patient is in a supine or lateral position, without relieving the traction force on the leg. Such procedures include hip pinning, casting of femoral and tibial fractures, and hip spica casting. In other procedures, such as femur nailing, it is necessary to position the patient on one side and to pivot the legs around the hips in the forward direction.
Existing orthopedic tables provide for abduction and adduction in a variety of ways. Common to many existing tables is that the patient's foot is connected to a traction unit attached to the distal end of an elongate member, with abduction and adduction being effected by pivoting the elongate member around its proximal end, which in some cases comprises a pivot point designed to approximate the location of the patient's hip. Traction units, which secure the patient's feet and which apply traction forces to the legs via the feet, are located at the distal ends of the elongate members. During use, a patient's foot is strapped into one of the traction units and he or she is positioned on a back rest with his or her hips centered along the same vertical axis as the pivot points. Abduction or adduction of the desired leg is carried out by pivoting the elongate member associated with the leg sought to be adjusted around its associated pivot point.
The location of the elongate members with respect to the patient location varies between the existing orthopedic tables. For example, in one existing table the elongate members roll along the floor of the treatment room on a system of wheels. The proximal end of each elongate member is a pivot point which is intended to be co-axial with the hip several feet above it. At the other end of the elongate member, a traction unit mounting member extends upwardly from the elongate member and supports a traction unit for holding the patient's foot. The patient's back is supported by a back rest which is mounted on a pedestal extending vertically from the floor. The proximal end of each elongate member is coupled to the pedestal. Abduction and adduction are carried out by rolling the elongate member corresponding to the leg in traction along the floor such that it pivots around its pivot point, thereby carrying the leg around the pivot point.
In another table, the back rest which holds the patient is mounted to a pedestal rising vertically from the floor. The elongate members (commonly referred to as "spars") are coupled to the pedestal at the distal end of the back rest, just below the back rest, and extend cantilever-style from the pedestal. The traction units are coupled to the distal ends of the spars.
In a third type of existing orthopedic table, the elongate members are incorporated into a large framework positioned over the patient. The framework is a large structure supported by four posts extending vertically from the floor to frame a rectangular box around the patient. As with the first two units, the elongate members are substantially parallel to the location of the patient's legs, but in this type of table the elongate members are several feet above the patient. The traction units hang from a pair of substantially vertical members extending downwardly from the elongate members.
While each of the existing orthopedic tables described is effective for maintaining traction and for enabling abduction and adduction, these tables present difficulties when image intensification is used during the orthopedic procedure. An image intensification unit is comprised of an x-ray transmitter and an x-ray receiver positioned at the top and bottom, respectively, of a large C-shaped member. To use an image intensifier, the C-shaped member is positioned around the limb sought to be imaged. X-rays are directed at the limb by the x-ray transmitter and are received by the x-ray receiver. Image intensification units are mounted on a base having wheels so that the units may be rolled up to the patient for imaging and then rolled out of the way to allow the orthopedic procedure to proceed.
The first of the existing orthopedic tables described above presents difficulties with the use of an image intensifier in that when the patient's limbs are abducted, one or both of the elongate members extend broadly across the floor. The elongate members thus make it difficult to roll an image intensifier into position for imaging, since the base of the image intensifier can collide with the elongate members.
The second of the existing orthopedic tables described above also presents problems with respect to image intensification in that the spars are positioned so close to the patient's legs that they are within the imaging field. These spars, even when constructed from materials such as radiolucent carbon fiber, are not completely penetrable by x-rays. The x-ray images produced can therefore include images of the spars which are superimposed on the images of the legs and which therefore prevent clear images of the bones of the legs.
Although the third type of existing orthopedic table described above keeps the imaging area substantially free from hardware that can obstruct the imaging field or present obstacles to the positioning of the image intensifier within the imaging field, its extensive frame system renders it cumbersome, difficult to store, and highly immobile.
Moreover, because each of the above-described designs relies on a cumbersome system of members for affecting abduction and adduction, these leg traction systems are normally configured to be used only on a specific type of orthopedic table.
Also inherent with the first and second table designs is the problem of possible loss of traction during abduction and adduction. During abduction and adduction, the leg being moved must move along the are of a circle having a center co-axial with the location of the patient's hip, since the hip is the natural pivot point of the leg. If movement is not centered around the axis of the hip, the distance between the patient's hip and foot will be forced to change to accommodate rotation about the hip and will thereby cause increases and decreases in tension in the leg as the leg is abducted or adducted.
Table designs of the first and second type are sometimes problematic in that they often do not adequately align the pivot point of the elongate member with the hip location. These table designs utilize a single pedestal, which must be positioned to balance the patient's weight. Since the patient's center of mass is in the lower back region, the pedestals on these tables are located near the sacral region of the back. Because the pedestals are located at the sacral region, there is no room there for the pivot points of the elongate members. The pivots points are thus shifted from the proper hip location, thereby causing increase in and loss of traction during abduction and adduction.
The pedestal employed in the first and second table designs also limits the versatility of the tables. Patients requiring lower limb traction are often the victims of accidents in which multiple injuries have been sustained. During treatment of such patients it is desirable to obtain x-ray images of various regions of the body, such as the torso and upper limbs, without removing the patient from traction. Because the pedestals utilized in these tables are configured to balance and support the patient's weight, they extend fairly broadly beneath the back rest and thus prevent access to the upper body by the C-shaped image intensification unit.